package com.tentative.competition.common.utils;

import cn.afterturn.easypoi.excel.ExcelExportUtil;

import cn.afterturn.easypoi.excel.ExcelImportUtil;

import cn.afterturn.easypoi.excel.entity.ExportParams;

import cn.afterturn.easypoi.excel.entity.ImportParams;

import org.apache.poi.ss.usermodel.Workbook;

import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.net.URLEncoder;

import java.util.List;

import java.util.NoSuchElementException;



public class MyExcelUtils {
    /**
     * 功能描述：复杂导出Excel，包括文件名以及表名,不创建表头
     *
     * @param list      导出的实体类
     * @param title     表头名称
     * @param sheetName sheet表名
     * @param pojoClass 映射的实体类
     * @param fileName
     * @param response
     * @return
     */

    public static void exportExcel(List<?> list, String title, String sheetName, Class<?> pojoClass,

                                   String fileName, HttpServletResponse response) {

        defaultExport(list, pojoClass, fileName, response, new ExportParams(title, sheetName));

    }


    /**
     * 功能描述：默认导出方法
     *
     * @param list         导出的实体集合
     * @param fileName     导出的文件名
     * @param pojoClass    pojo实体
     * @param exportParams ExportParams封装实体
     * @param response
     * @return
     */

    private static void defaultExport(List<?> list, Class<?> pojoClass, String fileName,

                                      HttpServletResponse response, ExportParams exportParams) {

        Workbook workbook = ExcelExportUtil.exportExcel(exportParams, pojoClass, list);

        if (workbook != null) {

            downLoadExcel(fileName, response, workbook);

        }

    }


    /**
     * 功能描述：Excel导出
     *
     * @param fileName 文件名称
     * @param response
     * @param workbook Excel对象
     * @return
     */

    private static void downLoadExcel(String fileName, HttpServletResponse response,

                                      Workbook workbook) {

        try {

            response.setCharacterEncoding("UTF-8");

            response.setHeader("content-Type", "multipart/form-data");

            response.setHeader("Content-Disposition",

                    "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));

            workbook.write(response.getOutputStream());


        } catch (IOException e) {

            throw new RuntimeException(e);

        }

    }


    /**
     * 功能描述：根据接收的Excel文件来导入Excel,并封装成实体类
     *
     * @param file       上传的文件
     * @param titleRows  表标题的行数
     * @param headerRows 表头行数
     * @param pojoClass  Excel实体类
     * @return
     */

    public static <T> List<T> importExcel(MultipartFile file, Integer titleRows, Integer headerRows,

                                          Class<T> pojoClass) {

        if (file == null) {

            return null;

        }

        ImportParams params = new ImportParams();

        params.setTitleRows(titleRows);

        params.setHeadRows(headerRows);

        List<T> list = null;

        try {

            list = ExcelImportUtil.importExcel(file.getInputStream(), pojoClass, params);

        } catch (NoSuchElementException e) {

            throw new RuntimeException("excel文件不能为空");

        } catch (Exception e) {

            throw new RuntimeException(e.getMessage());


        }

        return list;

    }

}
